ORIGINAL ARTICLE
Detection of scar dehiscence at delivery in women with prior cesarean section OFERGEMER,SHMUELSEGALAND Essi SASSOON From the Department of Obstetrics and Gynecology, Barzilai Medical Center, Ashkelon, affiliated to Ben-Gurion University of the Negev, Beer-Sheva, Israel
Acta Obstet Gynecol Scand 1992; 71: 54Q-542
Transcervical examination of a prior cesarean scar after vaginal delivery is commonly advised. A retrospective study of 1023 parturients with prior cesarean delivery was undertaken, 475 of whom delivered vaginally. Thirteen cases of scar dehiscence were found at laparotomy, and only one case was discovered by transcervical examination. The value of routine postdelivery examination of uterine scar is doubtful. Key words: previous cesarean section; uterine dehiscence; trial of labor Submitted November 29, 1991 Accepted February 15, 1992
The preponderance of medical literature traditionally advocates routine postpartum transcervical revision of the uterine scar following vaginal delivery in patients with a prior cesarean section, in order to explore the possibility of dehiscence (1,2,5,9,10). However, uterine defects are rare, and their management is controversial (3), so that the salutary value of the procedure is doubtful. The purpose of this study was to retrospectively analyze the overall incidence of uterine dehiscence discovered at delivery, assessing the value of routine transcervical examination.
Patients and methods The records of 1023 consecutive patients with one or more previous cesarean section were reviewed retrospectively. All patients delivered at the Barzilai Medical Center in Ashkelon, Israel, between January 1985 and June 1991. The records were divided into two groups of patients: those who electively submitted to a cesarean section and those who were allowed a trial of labor. The state of the uterine scar was observed in every patient undergoing a cesarean section. and manual transcervical revision of the
0Acra Ohster Gynecol Scand
71 (1992)
uterine scar was routinely performed following vaginal deliveries. Obstetrical management policy allowed each patient with one previous lower uterine segment scar a trial of labor, except when there were indications for a repeat cesarean section. Trial of labor was defined as induced or spontaneous labor in a patient with prior cesarean section ( 5 ) . Induction and stimulation methods used in labor were artificial rupture of membranes and breast stimulation. Oxytocin and local anesthesia were not employed; analgesia was provided by i.v. meperidine and promethazine. Fetal heart rate and uterine activity were continuously monitored during labor. True rupture denotes separation of the scar, with hemorrhage or fetal distress requiring immediate intervention. Dehiscence is defined as silent separation of a scar incidentally diagnosed at laparotomy o r vaginal examination, with no fetal or maternal compromise (4).
Results Of the 17,299 patients who delivered during the study period, 1023 women had had at least one pre-
Scar dehiscence discovered transcervically at delivery
541
Table I. Distribution of 1023 women with a previous Cesarean section and uterine scar dehiscence rates Women undergoing TOL
Elective Cesarean section
Repeated Cesarean (elective and failed TOL)
Total
Successful
Rates (%") n
63 64711023
73 4751647
37 37611023
54 54811023
Dehiscence rates (Yo) n
1.2 81647
0.2 11475
1.6 61376
2.4 131548
TOL = trial of labor
vious cesarean. The distribution of study population and dehiscence rates is given in Table I. The overall dehiscence rate was 1.4%. One patient undergoing a trial of labor had a true rupture, an incidence of 0.15%. The routine transcervical examination revealed two suspected cases of dehiscence; both parturients underwent laparotomy, but the preoperative diagnosis was confirmed in only one case.
Discussion In the literature, the incidence of scar separation following a low transverse uterine incision is 1-2.8% (2,3, l l ) , true rupture accounting for 0.17-0.6% ( 5 , 6 ) .Our results compare favorably. As in previous reports ( 3 ) , we found the incidence of dehiscence t o be the same in patients who underwent elective repeat cesarean section as in those who underwent labor. A greater incidence of dehiscence was noted at laparotomy than by transcervical examination. This discrepancy has also been noted by others (4, l l ) , who have attributed it, as we do, to better scar assessment at section. The validity of transcervical diagnosis is only tentative, as in our experience. Kolle et al. (7), too, failed to confirm scar separation at laparotomy in more than half of the cases. The management of a uterine defect identified transcervically is controversial. Asymptomatic dehiscence has been left untreated, with no apparent adverse consequences ( 2 , 5 ) . Exploratory laparotomy and operative repair are warranted in an unstable patient who is bleeding significantly; many authorities, however, refrain from intervention in asymptomatic, nonbleeding patients ( 3 ) . It is also uncertain whether the information gained by detecting scar separation has prognostic value for the management of future pregnancies. Scar separation often occurs prior to labor. Labor and vaginal delivery are usually not affected by lower segment 'window' ( 3 ) . Meehan et al. ( 5 ) reported two patients with bloodless, unrepaired dehiscence who had subsequent elective cesareans with no evidence
of scar dehiscence. Although elective repeated cesarean delivery is recommended, vaginal delivery has been reported after nonrepair of such lower segment separation (8). It should be borne in mind that transcervical examination is an invasive procedure, and may place the patient at risk of infection. Moreover, a manual examination may inadvertently convert a partial separation into a complete dehiscence. In our series, only one case of uterine dehiscence was discovered by manual examination of 475 patients. Transcervical examination probably failed to uncover some cases, as the rate of dehiscence observed at surgery was much higher. A s has been discussed, intervention is not mandatory when dehiscence is suspected. Thus, when viewed with respect to the yield and potential benefits, the value of routine examination becomes doubtful.
References 1. Saldana RL, Schulman H, Reuss L. Management of pregnancy after cesarean section. Am J Obstet Gynecol 1979; 135: 55541. 2. Lavin JP, Stephens RJ, Miodovnik M, Barden TP. Vaginal delivery in patients with a prior cesarean section. Obstet Gynecol 1982; 59: 13548. 3. Clark SL. Rupture of the scarred uterus. Obstet Gynecol Clin North Am 1988; 15: 736-44. 4. Tahilramaney MP, Boucher M, Eglinton GS, Beal M, Phelan JP. Previus cesarean section and trial of labor. J Reprod Med 1984; 29: 17-21. 5. Meehan FP, Burk G, Kehoe JT, Magani IM. True rupturelscar dehiscence in delivery following prior section. Int J Gynecol Obstet 1990; 31: 249-55. 6. Flamm BL, Newman LA, Thomas SJ, Fallon D, Yoshida MM. Vaginal birth after cesarean delivery. Results of a 5-year multicenter collaborative study. Obstet Gynecol 1990; 76: 7 5 M . 7. Kolle FM, Prinz W, Jonatha WD. The course of labor following cesarean section with special reference to epidural anasthesia. Geburtshilfe - Frauenheilkd 1984; 44: 146-9. 8. Phelan JP, Clark SC, Diaz F, Paul RH. Vaginal birth after cesarean. 1989; 157: 1510-5.
0Acta Ubsrer Gynecol Scund 71 (1YY2)
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0. Cemer et al.
9. Case BD, Corcoran R, Jeffcoate N. Cesarean section and its place in modern obstetric practice. J Obstet Gynecol Br Commonw 1971; 78: 203-14. 10. Dunn LJ. Cesarean section and other obstetric operations. In Scott JR, Disaia PJ, Hammond CB, Spellacy WN, Eds. Danforth’s Obstetrics and Gynecology 6th ed. Philadelphia: JB Lippincott, 1990: 641. 11. Rosen MG, Dichinson JC, Westhoff CL. Vaginal birth after cesarean: a meta-analysis of morbidity and morality. Obstet Gynecol 1991; 77: 465-70.
O A c l a Ohsrer Gynecol Scand 71 (1992)
Address for correspondence: Dr. 0. Gemer, M.D. Department Of Obstetrics and Center Ashkelon Israel 78306
Detection of scar dehiscence at delivery in women with prior cesarean section OFERGEMER,SHMUELSEGALAND Essi SASSOON From the Department of Obstetrics and Gynecology, Barzilai Medical Center, Ashkelon, affiliated to Ben-Gurion University of the Negev, Beer-Sheva, Israel
Acta Obstet Gynecol Scand 1992; 71: 54Q-542
Transcervical examination of a prior cesarean scar after vaginal delivery is commonly advised. A retrospective study of 1023 parturients with prior cesarean delivery was undertaken, 475 of whom delivered vaginally. Thirteen cases of scar dehiscence were found at laparotomy, and only one case was discovered by transcervical examination. The value of routine postdelivery examination of uterine scar is doubtful. Key words: previous cesarean section; uterine dehiscence; trial of labor Submitted November 29, 1991 Accepted February 15, 1992
The preponderance of medical literature traditionally advocates routine postpartum transcervical revision of the uterine scar following vaginal delivery in patients with a prior cesarean section, in order to explore the possibility of dehiscence (1,2,5,9,10). However, uterine defects are rare, and their management is controversial (3), so that the salutary value of the procedure is doubtful. The purpose of this study was to retrospectively analyze the overall incidence of uterine dehiscence discovered at delivery, assessing the value of routine transcervical examination.
Patients and methods The records of 1023 consecutive patients with one or more previous cesarean section were reviewed retrospectively. All patients delivered at the Barzilai Medical Center in Ashkelon, Israel, between January 1985 and June 1991. The records were divided into two groups of patients: those who electively submitted to a cesarean section and those who were allowed a trial of labor. The state of the uterine scar was observed in every patient undergoing a cesarean section. and manual transcervical revision of the
0Acra Ohster Gynecol Scand
71 (1992)
uterine scar was routinely performed following vaginal deliveries. Obstetrical management policy allowed each patient with one previous lower uterine segment scar a trial of labor, except when there were indications for a repeat cesarean section. Trial of labor was defined as induced or spontaneous labor in a patient with prior cesarean section ( 5 ) . Induction and stimulation methods used in labor were artificial rupture of membranes and breast stimulation. Oxytocin and local anesthesia were not employed; analgesia was provided by i.v. meperidine and promethazine. Fetal heart rate and uterine activity were continuously monitored during labor. True rupture denotes separation of the scar, with hemorrhage or fetal distress requiring immediate intervention. Dehiscence is defined as silent separation of a scar incidentally diagnosed at laparotomy o r vaginal examination, with no fetal or maternal compromise (4).
Results Of the 17,299 patients who delivered during the study period, 1023 women had had at least one pre-
Scar dehiscence discovered transcervically at delivery
541
Table I. Distribution of 1023 women with a previous Cesarean section and uterine scar dehiscence rates Women undergoing TOL
Elective Cesarean section
Repeated Cesarean (elective and failed TOL)
Total
Successful
Rates (%") n
63 64711023
73 4751647
37 37611023
54 54811023
Dehiscence rates (Yo) n
1.2 81647
0.2 11475
1.6 61376
2.4 131548
TOL = trial of labor
vious cesarean. The distribution of study population and dehiscence rates is given in Table I. The overall dehiscence rate was 1.4%. One patient undergoing a trial of labor had a true rupture, an incidence of 0.15%. The routine transcervical examination revealed two suspected cases of dehiscence; both parturients underwent laparotomy, but the preoperative diagnosis was confirmed in only one case.
Discussion In the literature, the incidence of scar separation following a low transverse uterine incision is 1-2.8% (2,3, l l ) , true rupture accounting for 0.17-0.6% ( 5 , 6 ) .Our results compare favorably. As in previous reports ( 3 ) , we found the incidence of dehiscence t o be the same in patients who underwent elective repeat cesarean section as in those who underwent labor. A greater incidence of dehiscence was noted at laparotomy than by transcervical examination. This discrepancy has also been noted by others (4, l l ) , who have attributed it, as we do, to better scar assessment at section. The validity of transcervical diagnosis is only tentative, as in our experience. Kolle et al. (7), too, failed to confirm scar separation at laparotomy in more than half of the cases. The management of a uterine defect identified transcervically is controversial. Asymptomatic dehiscence has been left untreated, with no apparent adverse consequences ( 2 , 5 ) . Exploratory laparotomy and operative repair are warranted in an unstable patient who is bleeding significantly; many authorities, however, refrain from intervention in asymptomatic, nonbleeding patients ( 3 ) . It is also uncertain whether the information gained by detecting scar separation has prognostic value for the management of future pregnancies. Scar separation often occurs prior to labor. Labor and vaginal delivery are usually not affected by lower segment 'window' ( 3 ) . Meehan et al. ( 5 ) reported two patients with bloodless, unrepaired dehiscence who had subsequent elective cesareans with no evidence
of scar dehiscence. Although elective repeated cesarean delivery is recommended, vaginal delivery has been reported after nonrepair of such lower segment separation (8). It should be borne in mind that transcervical examination is an invasive procedure, and may place the patient at risk of infection. Moreover, a manual examination may inadvertently convert a partial separation into a complete dehiscence. In our series, only one case of uterine dehiscence was discovered by manual examination of 475 patients. Transcervical examination probably failed to uncover some cases, as the rate of dehiscence observed at surgery was much higher. A s has been discussed, intervention is not mandatory when dehiscence is suspected. Thus, when viewed with respect to the yield and potential benefits, the value of routine examination becomes doubtful.
References 1. Saldana RL, Schulman H, Reuss L. Management of pregnancy after cesarean section. Am J Obstet Gynecol 1979; 135: 55541. 2. Lavin JP, Stephens RJ, Miodovnik M, Barden TP. Vaginal delivery in patients with a prior cesarean section. Obstet Gynecol 1982; 59: 13548. 3. Clark SL. Rupture of the scarred uterus. Obstet Gynecol Clin North Am 1988; 15: 736-44. 4. Tahilramaney MP, Boucher M, Eglinton GS, Beal M, Phelan JP. Previus cesarean section and trial of labor. J Reprod Med 1984; 29: 17-21. 5. Meehan FP, Burk G, Kehoe JT, Magani IM. True rupturelscar dehiscence in delivery following prior section. Int J Gynecol Obstet 1990; 31: 249-55. 6. Flamm BL, Newman LA, Thomas SJ, Fallon D, Yoshida MM. Vaginal birth after cesarean delivery. Results of a 5-year multicenter collaborative study. Obstet Gynecol 1990; 76: 7 5 M . 7. Kolle FM, Prinz W, Jonatha WD. The course of labor following cesarean section with special reference to epidural anasthesia. Geburtshilfe - Frauenheilkd 1984; 44: 146-9. 8. Phelan JP, Clark SC, Diaz F, Paul RH. Vaginal birth after cesarean. 1989; 157: 1510-5.
0Acta Ubsrer Gynecol Scund 71 (1YY2)
542
0. Cemer et al.
9. Case BD, Corcoran R, Jeffcoate N. Cesarean section and its place in modern obstetric practice. J Obstet Gynecol Br Commonw 1971; 78: 203-14. 10. Dunn LJ. Cesarean section and other obstetric operations. In Scott JR, Disaia PJ, Hammond CB, Spellacy WN, Eds. Danforth’s Obstetrics and Gynecology 6th ed. Philadelphia: JB Lippincott, 1990: 641. 11. Rosen MG, Dichinson JC, Westhoff CL. Vaginal birth after cesarean: a meta-analysis of morbidity and morality. Obstet Gynecol 1991; 77: 465-70.
O A c l a Ohsrer Gynecol Scand 71 (1992)
Address for correspondence: Dr. 0. Gemer, M.D. Department Of Obstetrics and Center Ashkelon Israel 78306
